Amplifier



Nov. l, 1927. 1,647,736

- F. C. KOLLATH nrLIrrsn Filed )lay 19. 1924 Patented Nov. 1 1927.

UNITED STATES PATENT OFI-'ica Application led Iay 18,

My invention relates to radio fre uency amplifiers, and is especially adapted or inter-stage coupling in radio recelvers.

One ot' the objects of my invention is to provide an amplifier comprised of a plurality of primary and secondary co1ls arranged in such a manner that a closed magnetlc field is formed, and which may be placed in close proximity to a similar amplifier or to other inductances Without causing undesirable eti'ects.

Another object of my invention is to provide a device which is cheap to manufacture, easy to assemble and of few parts.

Further objects of my invention will appear from the detailed description to follow and from the appended claims.

Realizing that my invention may be varied in its physical embodiment without departing from the spirit of the invention, I desire it to be understood that'the specific construction and form herein shown is to be taken as illustrative and not in a limited sense.

In the accompanying drawings like p0rtions of the device are designated by like characters thruout the several figures.

Fig. l. is a side elevation of my invention and showing the primary soldering lugs.

Fig. 2 is a vertical, transverse, sectional elevation through Fig. 1.

Fig. 3 is a side elevation of the secondary side and' showing the secondary lugs.

Fig. 4 is a vertical section taken. on a line corresponding to the dividing line of the casing, the coils and condenser being shown in full lines.

Fig. 5 is a bottom view of the device as shown in Fig. 3.

Fig. 6 is a diagrammatic view showing the coil windings and taps and their relation to each other.

Referring now to the drawings iIL detail, the invention as shown comprises an insulating casing, preferably made in two identical and interchangeable halves 1 anu z forming the sides of the casing, and which for convenience will hereafter he called the. primary and secondary side respectlvely.

These sides may be made of any suitable insulating materlal such as bakelite or hard rubber.

The halves are secured together by means of the eyelets 3 and are designed to provide 1924. Serial No. 714,208.

a substantially circular chamber 4, in which are supported the semi-circular or D shaped coils 5 and 6.

The halves of the casing are provided with flanges 7 and 8 forming the walls of the chamber 9 which is adapted to receive the condenserflO. This condenser is of the usual fixed type used in radio reception, and is preferably rectangular in shape, and is laid in the chamber 9 in such a manner that it eifectually closes the opening 11 between the chambers 4 and 9, the wax 12 is then poured into the chamber 9 securing the condenser in place and effectively insulating it. Holes 13 are provided in the flanges for mounting the device.

Soldering lugs are provided on the primary casing 1. Theseare secured by means of the eyelets 15.

Eyelets are used for securing the soldering lugs so that the ends of the primary coils maybe passed thru them and wound around and soldered to the lugs on the outside of the casing. Lugs 16 are also provided on the opposite or secondary half of the casing and are also secured by means of eyelets, the terminals of the secondary are passed thru the eyelets and soldered in the same manner as on the primary side. On the secondary side is also provided a third lug 17 also secured by an eyelet and to whlich is secured a tap from the secondary co1 s.

It will be noted that the manner in which the coils are arranged forms a closed magnetic eld. After the coils are wound and connected together as shown in Fig. 6, the primary is one continuous winding and the secondary is another continuous winding thru both coils and in the form of a figure 8.

It is found in practice that these amplifiers may be set side by side in radio receiving sets without causing undesirable effects.

It will be noted by reference to Fig. 6 that the coils are formed by winding the primary and secondary wires at the same time until a suilicient amount of primary is wound on, then the primary is cut off and the winding of the secondary is continued until the desired ratio is obtained. The two D shaped coils are then placed in the casing and the primaries are connected together as well as the secondaries thus forming a figure 8 coil having a'. continuous primary and av contin-V uous secondary. A tap 18 is taken from the secondary between the two coils as shown in Fig 6 and is connected to the soldering lug 17. This is for use in neutralizing whlch is common practice in many radio receivers.

The condenser is connected to the secondary terminals 19 and 20 as shown and which are in turn connected to the soldering lugs 16. The primary terminals 21 and 22 are connected to the soldering lu 14.

Having thus full describe my invention, I claim as new an desireto secure by\Let ters Patent: i

1. An amplifier comprising a pair of D. shaped inductance coi s consistin of pri'- marg and secondary windings, sai primary win ings being connected together and said secondary winding being connected together to form continuous primary and continuous secondary windings, said windings being parallel to each other and substantially in the form of a figure 8, said coils bein in the same plane and having their fiat si es. arallel, a neutralizing tapy from the secon ary between lthe D sha ed coils, and a condenser connected across t e secondary terminals.

2. vAn insulating casing havmg a Substantially circular .chamber and a substantiall rectangular chamber at right angles to eac other, soldering lugs on said caslng and secured thereto by means of eyelets, a pair of D shaped coils in said circular chamber and having parallel primary and secondary windings, said primary windin bein connected together and said secon ary an said secondary windings being connected together in the form ofa ligure 8, the terminals of said primary windings assing thru said eyelets and being connected) to the soldering lugs on one side of said casing, the terminals of the secondary windings 'passin thru the eyelets and being connected to tile lugs on the opposite side of said casing, and a condenser connected across the terminals of the secondary windings and supported in the rectangular chamber in said casing.

In Witness whereof, I have hereunto subscribed my name.

FRANCIS C. KOLLATH. 

